Reinforced concrete frame beam structure for composite reinforcement and manufacturing method

Abstract

The present invention proposes a reinforced concrete frame beam structure and a manufacturing method for a composite reinforcement form, wherein the reinforced concrete frame beam structure includes a waved steel bar group, a stirrup group and a steel strand, wherein the waved steel bar group includes a plurality of parallel top waved steel bars and a plurality of parallel bottom waved steel bars; the top waved steel bars and the bottom waved steel bars each include at least one waved section; an isolation sleeve is sleeved on the waved section; the stirrup group includes a plurality of stirrups, each stirrup is wrapped around the outer wall of all waved steel bars and the bottom waved steel bars; the stirrups form a closed space; the steel strand is arranged between the top waved steel bars and the bottom waved steel bars; the steel strand passes through the closed space surrounded by all stirrups; an isolation sleeve is sleeved outside the steel strand. The present invention improves the deformation capacity of the frame structure by arranging the waved steel bars and the isolation sleeve; and improves the bearing capacity of the frame structure by arranging the steel strand and the isolation sleeve.

Description

Technical Field

[0001] The invention belongs to the technical field of anti-collapse of concrete frame beam structures, and in particular relates to a reinforced concrete frame beam structure in a composite reinforcement form and a manufacturing method thereof. Background Art

[0002] When a concrete frame structure encounters unexpected extreme loads, such as explosions, impacts, and fires, the damage or destruction of its local components may cause the collapse of the entire structure, leading to serious consequences. During the entire process of its collapse, the reinforced concrete frame structure will develop into a beam-compression arch mechanism and a catenary mechanism. The catenary mechanism can usually provide resistance that exceeds the bending limit bearing capacity of the compression arch stage, and it plays the role of the last line of defense to prevent continuous collapse. However, the transformation from the compression arch mechanism to the catenary mechanism usually leads to the fracture of the steel bars near the interface between the beam and column. In the actual continuous collapse process, the components are required to have not only sufficient bearing capacity, but also sufficient ductility and rotation capacity, so as to develop the catenary mechanism. The large deformation in the catenary stage is mainly caused by the rotation of the beam-column joint, including bending rotation and fixed end rotation. The fixed end rotation depends on the deformation and local slip of the steel anchor section under complex stress, which is easy to cause the steel bars at the beam end to break in practice.

[0003] In the prior art, the ability of reinforced concrete frames to resist progressive collapse depends largely on the load redistribution outside the failure area and the bearing capacity of horizontal components. Therefore, the strength of reinforced concrete frame beams is a major concern in most current anti-collapse design specifications. The key factors affecting whether the catenary mechanism of concrete frames can be effectively activated are the steel bar configuration and related structural measures in the frame beams. The steel bar configuration directly affects the connection performance, rotation capacity and bearing capacity of the components. The structural measures at the beam-column joint determine the rotation deformation capacity of the beam end. Summary of the invention

[0004] The purpose of the present invention is to provide a reinforced concrete frame beam structure and a manufacturing method for composite reinforcement. By providing wave-forming steel bars and isolation sleeves, the deformation capacity of the frame structure is improved; by providing steel strands and isolation sleeves, the bearing capacity of the frame structure is improved. Thus, the reinforced concrete frame beam structure can effectively prevent the continuous collapse of the structure. To achieve the above purpose, the present invention adopts the following technical solutions:

[0005] A reinforced concrete frame beam structure for composite reinforcement, comprising:

[0006] The corrugated steel bar group comprises a plurality of parallel top corrugated steel bars and a plurality of parallel bottom corrugated steel bars; the top corrugated steel bars and the bottom corrugated steel bars each comprise at least one corrugated section; an isolation sleeve is sleeved on the corrugated section;

[0007] A stirrup group, comprising a plurality of stirrups, each of which is wrapped around the outer walls of all corrugated steel bars and the bottom corrugated steel bars; the stirrups enclose a closed space;

[0008] The steel strand is arranged between the top corrugated steel bars and the bottom corrugated steel bars; the steel strand passes through the closed space surrounded by all the stirrups; an isolation sleeve is arranged outside the steel strand.

[0009] Preferably, the wave-starting section includes two oblique straight line sections, which are connected via a first transition section; and one end of the two oblique straight line sections away from the first transition section is respectively connected to the second transition section.

[0010] Preferably, the opening direction of the isolation sleeve is the same as the waving direction of the waving section.

[0011] Preferably, the waving sections of the top waving steel bars are arranged alternately with the waving sections of the bottom waving steel bars.

[0012] Preferably, the wave-generating direction of the wave-generating section is toward the inside of the frame beam structure.

[0013] Preferably, all of the top corrugated steel bars are located at the same horizontal height; and all of the bottom corrugated steel bars are located at the same horizontal height.

[0014] Preferably, the distribution density of stirrups close to the waving section is greater than the distribution density of stirrups far from the waving section.

[0015] Preferably, the steel strands are unbonded steel strands.

[0016] A method for manufacturing a reinforced concrete frame beam structure in a composite reinforcement form, based on the reinforced concrete frame beam structure in a composite reinforcement form, comprises the following steps: an isolation sleeve is sleeved on the wave-generating section, then the top wave-generating steel bars and the bottom wave-generating steel bars are fixed by tying a stirrup group, then the steel strand is sleeved in an isolation sleeve, and finally the isolation sleeve is set between the top wave-generating steel bars and the bottom wave-generating steel bars.

[0017] Compared with the prior art, the advantages of the present invention are:

[0018] (1) When subjected to a large external force, the deformation of the corrugated steel bars first occurs in the corrugated section. After the corrugated section is completely straightened, a deformation form similar to that of traditional straight steel bars occurs, thereby improving the deformation capacity of the frame structure.

[0019] (2) The wave section is contained in the isolation sleeve, which can effectively isolate the wave section from the concrete, so that the steel bars in the wave section have enough space to be completely straightened. At the same time, it can prevent the steel bars in the wave section from exerting pressure on the concrete during the straightening process, causing the wave section to collapse from the beam, resulting in large cracks in the cross section and reducing the ultimate bearing capacity of the beam cross section in the elastic-plastic stage. Therefore, the isolation sleeve increases the bearing capacity of the frame structure.

[0020] (3) The isolation sleeve isolates the steel strand from the concrete, so there is no direct contact between the steel strand and the concrete. Under the action of external loads, the steel strand can deform relative to the concrete. In the large deformation stage, the steel strand bends greatly and the stress direction at each point changes. As the stress of the steel strand continues to increase, its vertical component also continues to increase. Therefore, the steel strand can use its tensioning capacity to effectively resist the vertical load. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 A three-dimensional diagram of a reinforced concrete frame beam structure in a composite reinforcement form according to an embodiment of the present invention;

[0022] Figure 2 It is a schematic diagram of the installation of a reinforced concrete frame beam structure and columns in a composite reinforcement form according to an embodiment of the present invention;

[0023] Figure 3 for Figure 2 Installation diagram with the isolation sleeve removed;

[0024] Figure 4 for Figure 1 Structural diagram of corrugated steel bars;

[0025] Figure 5 for Figure 4 Diagram of the straightening process of the middle starting band;

[0026] Figure 6 This is a cross-sectional view of a reinforced concrete frame beam structure for composite reinforcement in an embodiment of the present invention, at the isolation sleeve;

[0027] Figure 7(a) shows Figure 1 Schematic diagram of the installation of the isolation sleeve and the wave-starting band;

[0028] Figure 7(b) shows Figure 1 Structural diagram of the middle isolation sleeve;

[0029] Figure 8 The comparison diagram of bending moment of reinforced concrete frame beam structure under vertical load and horizontal load respectively;

[0030] Fig. 9 Schematic diagram of the reinforced concrete frame beam structure resisting progressive collapse under the condition of middle column failure.

[0031] Among them, 100-column, 200-top corrugated steel bar, 210-corrugated section, 220-straight section, 211-inclined straight section, 212-first transition section, 213-second transition section, 300-unbonded steel strand, 400-stirrups, 230-isolation sleeve. DETAILED DESCRIPTION

[0032] The present invention will be described in more detail below in conjunction with the schematic diagram, wherein the preferred embodiment of the present invention is shown, and it should be understood that those skilled in the art can modify the present invention described herein, and still achieve the beneficial effects of the present invention. Therefore, the following description should be understood as being widely known to those skilled in the art, and not as a limitation of the present invention.

[0033] like Figure 1 As shown, a reinforced concrete frame beam structure for composite reinforcement includes a wave reinforcement group, an isolation sleeve 230, a stirrup group, a steel strand 300 and an isolation sleeve.

[0034] like Figure 2~3 As shown, the wave-forming steel bar group of the reinforced concrete frame beam structure is orthogonally arranged between two adjacent columns 100, and then the reinforced concrete frame beam structure is poured with concrete.

[0035] The specific structure of the reinforced concrete frame beam structure is as follows:

[0036] The waved steel bar group includes a plurality of parallel top waved steel bars 200 and a plurality of parallel bottom waved steel bars. All the top waved steel bars 200 are located at the same level; and all the bottom waved steel bars are located at the same level.

[0037] The top corrugated steel bar 200 and the bottom corrugated steel bar have the same structure, both of which include a straight section 220 and at least one corrugated section 210. Specifically, Figure 4 As shown, the wave section 210 includes two oblique straight line segments 211, and the two oblique straight line segments 211 are connected by a first transition segment 212; one end of the two oblique straight line segments 211 away from the first transition segment 212 is respectively connected to the second transition segment 213, and the second transition segment 213 is connected to the straight line segment 220 of the steel bar. That is, the steel bar structure at the wave section 210 is as follows: a straight line segment 220, a second transition segment 213, an oblique straight line segment 211, a first transition segment 212, another oblique straight line segment 211, another second transition segment 213 and another straight line segment 220 are connected in sequence. In this embodiment, the two oblique straight line segments 211 form a certain angle, and the angle can be 30°~150°, but is not limited to this. Figure 5As shown, when subjected to a large external force, the deformation of the corrugated steel bar first occurs in the corrugated section 210, and the angle between the oblique straight section 211 and the straight section 220 gradually decreases. As the external force increases, the angle between the oblique straight section 211 and the straight section 220 gradually decreases to 0, that is, the corrugated section 210 is straightened. After the corrugated section 210 is completely straightened, a deformation similar to that of a traditional straight steel bar occurs. Therefore, under the condition of the same steel bar strength, the reinforced concrete frame structure has a strong deformation capacity and can effectively prevent the continuous collapse of the structure.

[0038] Preferably, the waving sections 210 of the top waving steel bars 200 are arranged alternately with the waving sections 210 of the bottom waving steel bars to avoid shear damage of the beam under normal use; the waving positions of the same row of steel bars (top waving steel bars 200 or bottom waving steel bars) are the same, and the waving direction of the waving sections 210 is toward the inside of the frame beam structure.

[0039] Preferably, the distance between the wave section 210 at the top of the beam and the adjacent beam-column node area is closer than the distance between the wave section 210 at the bottom of the beam and the adjacent beam-column node area, and the wave sections 210 at the top and bottom of the beam are respectively located on both sides of the minimum bending moment of the beam structure under the vertical load. Therefore, under the vertical load, the steel bar wave sections 210 at the top and bottom of the beam are both on the tension side; the wave section 210 of the waved steel bar is close to the minimum bending moment of the reinforced concrete frame beam structure under the vertical load, which will not affect the safety of the normal use of the structure.

[0040] In this embodiment, by controlling the structure and size of the waving section 210, waving steel bars with different deformation capabilities can be formed. In this embodiment, a triangular waving method is adopted. In addition, the waving section 210 can also adopt other shapes such as a parabola or a superposition of different shapes.

[0041] The top corrugated steel bars 200 and the bottom corrugated steel bars are both integrally formed structures and can be formed by processing traditional straight steel bars, such as the cold processing technology of steel bars. The technology is simple and the forming is convenient, which can effectively reduce the cost.

[0042] The isolation sleeve 230 is used to isolate the concrete and the wave-starting section 210 to ensure that the wave-starting section 210 is fully straightened. As shown in Figure 7 (a) and Figure 7 (b), the isolation sleeve 230 is mounted on the wave-starting section 210. The opening direction of the isolation sleeve 230 is the same as the wave-starting direction of the wave-starting section 210. The isolation sleeve 230 can effectively isolate the wave-starting section 210 from the concrete, leaving enough space for the wave-starting section 210 to ensure that the wave-starting section 210 of the steel bar can be fully straightened when subjected to a large external force, thereby ensuring the deformation capacity. The isolation sleeve 230 can effectively isolate the wave-starting section 210 from the concrete, preventing the steel bar of the wave-starting section 210 from exerting pressure on the concrete during the straightening process, causing the wave-starting section 210 to collapse from the beam, resulting in larger cracks in the section, and affecting the bearing capacity of the plastic hinge. Furthermore, if Figure 6 As shown, the waving section 210 of the top waving steel bar 200 located at the top of the beam is convex in an oblique downward direction, and the waving section 210 of the bottom waving steel bar located at the bottom of the beam is convex in an oblique upward direction. The waving section 210 of the waving steel bar is convex inward at a certain angle with the vertical plane, and the angle is 30-75°, but not limited thereto. The effective height of the beam section is the distance from the edge of the compression zone to the center of gravity of the tensile steel bar. Under the same waving degree, compared with the vertical waving, the effective height of the oblique waving beam section is larger, the moment of the total tension of the tensile steel bar on the center of the compression zone is larger, and the bending bearing capacity of the beam is larger.

[0043] The stirrup group includes a plurality of stirrups 400, each of which is wrapped around the outer walls of all the wave-generating steel bars and the bottom wave-generating steel bars; the stirrups 400 enclose a closed space; the distribution density of the stirrups 400 close to the wave-generating section 210 is greater than the distribution density of the stirrups 400 far from the wave-generating section 210, that is, the stirrups 400 are densely arranged near the wave-generating section 210 of the wave-generating steel bars, so that the cross-section of the wave-generating section 210 has better rotation ability after yielding, and fully dissipates the seismic energy.

[0044] The steel strand 300 is arranged between the top wave reinforcement 200 and the bottom wave reinforcement; the steel strand 300 passes through the closed space surrounded by all the stirrups 400; an isolation sleeve is arranged outside the steel strand 300, and the isolation sleeve is used to isolate the concrete and the steel strand 300. In this embodiment, the steel strand 300 is an unbonded steel strand 300, which is in a relaxed state or a low stress state, and has an enhancing effect on the anti-collapse bearing capacity of the reinforced concrete frame beam structure. The steel strand 300 can deform relative to the concrete under the action of external loads because it has no direct contact with the concrete. The unbonded steel strand 300 has a strong pulling ability. In the large deformation stage, the steel strand 300 bends greatly and the stress direction of each point changes. As the stress of the steel strand 300 continues to increase, its vertical component force also continues to increase, playing an important role in resisting vertical loads.

[0045] The manufacturing method of the reinforced concrete frame beam structure in the composite reinforcement form includes the following steps: an isolation sleeve 230 is sleeved on the wave section 210, and then the top wave steel bar 200 and the bottom wave steel bar are fixed by the stirrups 400 in the stirrup group, and then the steel strand 300 is sleeved in an isolation sleeve, and finally the isolation sleeve is set between the top wave steel bar 200 and the bottom wave steel bar.

[0046] Figure 8 The figure shows the bending moment comparison diagram of the reinforced concrete frame beam structure under the vertical uniformly distributed load F1 and the horizontal concentrated load F2. Figure 8 As shown in FIG. 1 , under the action of vertical load F1, the bending moment near the steel bar wave section 210 of the frame beam structure is close to zero. Under normal use, the reinforced concrete frame beam structure mainly bears vertical loads, such as the building's own weight and floor live load, and the bending moment near the location where the steel bar wave section 210 is set is small. Although the setting of the steel bar wave section 210 weakens the cross-sectional bearing capacity, due to the oblique setting of the wave direction (such as Figure 6 As shown in FIG. 1 ), the wave-generating effect does not weaken the bearing capacity of the beam much, and an unbonded steel strand 300 is added to the middle layer of the beam to enhance the bearing capacity, so the cross-sectional bearing capacity is still sufficient.

[0047] Fig. 9 The figure shows the resistance of the frame beam structure to progressive collapse under the condition of middle column failure. Fig. 9 As shown in FIG. 1 , the local continuous collapse occurs under the action of the failure of the middle column. The bottom steel bar wave section 210 at the bottom of the beam on both sides of the middle column is straightened, and the steel bar wave section 210 at the top of the beam at the far end of the middle column is straightened. In this embodiment, Fig. 9 As shown, "middle column failure" refers to the failure of the column 100 located in the middle position.

[0048] In summary, the reinforced concrete frame beam structure is equipped with both wave reinforcement and unbonded steel strand 300, striving to improve the action capacity of the catenary in the stage of continuous collapse and large deformation of the structure, without reducing the bearing capacity in the early stage of beam-compression arch action. Among them, the steel bar bending section is set at the beam end to delay the premature fracture of the steel bar; and the unbonded steel strand 300 is added to the middle layer of the beam, which helps to prevent accidental shear damage of the beam, improve the structure's tensioning capacity and bearing capacity, and solve the problem of the weakening of the early bending bearing capacity of the frame beam by the setting of the bent steel bar.

[0049] The above is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any technician in the relevant technical field, without departing from the scope of the technical solution of the present invention, makes any form of equivalent replacement or modification to the technical solution and technical content disclosed in the present invention, which does not depart from the content of the technical solution of the present invention and still falls within the protection scope of the present invention.

Claims

1. A reinforced concrete frame beam structure for composite reinforcement, characterized in that: include: The corrugated steel bar group comprises a plurality of parallel top corrugated steel bars and a plurality of parallel bottom corrugated steel bars; the top corrugated steel bars and the bottom corrugated steel bars each comprise at least one corrugated section; an isolation sleeve is sleeved on the corrugated section; A stirrup group, comprising a plurality of stirrups, each of which is wrapped around the outer walls of all corrugated steel bars and the bottom corrugated steel bars; the stirrups enclose a closed space; The steel strand is arranged between the top corrugated steel bar and the bottom corrugated steel bar; the steel strand passes through the closed space surrounded by all the stirrups; an isolation sleeve is arranged outside the steel strand; the steel strand is in a relaxed state or a low stress state; The corrugated sections of the top corrugated steel bars are arranged alternately with the corrugated sections of the bottom corrugated steel bars; The wave-generating direction of the wave-generating section is toward the inside of the frame beam structure; The steel strands are unbonded steel strands.

2. The reinforced concrete frame beam structure for composite reinforcement according to claim 1, characterized in that: The wave-starting section includes two oblique straight line sections, which are connected via a first transition section; one end of the two oblique straight line sections away from the first transition section is respectively connected to the second transition section.

3. The reinforced concrete frame beam structure for composite reinforcement according to claim 1, characterized in that: The opening direction of the isolation sleeve is the same as the waving direction of the waving section.

4. The reinforced concrete frame beam structure for composite reinforcement according to claim 1, characterized in that: All the top corrugated steel bars are located at the same level; all the bottom corrugated steel bars are located at the same level.

5. The reinforced concrete frame beam structure for composite reinforcement according to claim 1, characterized in that: The stirrup distribution density close to the wave-starting section is greater than that far from the wave-starting section.

6. A method for manufacturing a reinforced concrete frame beam structure with composite reinforcement, based on the reinforced concrete frame beam structure with composite reinforcement as claimed in any one of claims 1 to 5, characterized in that: The following steps are involved: An isolation sleeve is put on the wave-starting section, and then the top wave-starting steel bars and the bottom wave-starting steel bars are fixed by tying the stirrup group, and then the steel strand is put in an isolation sleeve, and finally the isolation sleeve is set between the top wave-starting steel bars and the bottom wave-starting steel bars.

Images